with ranked_latitude as (
    select 
         lat_n
        ,row_number() over (order by lat_n) as lat_ranking
        ,(select count(*) from station) as no_of_rows
        from station group by lat_n
),
    median as (
        select lat_ranking from ranked_latitude
        where lat_ranking = (
            case
                when (no_of_rows)%2=0 then (no_of_rows+1)/2
                else (no_of_rows+1)/2
            end
        )
    )
    select round(lat_n,4) from ranked_latitude where 
    lat_ranking = (select * from median);